Thus the carrying capacity
of the wire is in practice nearly doubled, and recorders are busy
writing at both ends of the cable at once, as if the messages came up
out of the sea itself.
We have thus far followed out the recorder in its practical application
to submarine telegraphy. Let us now regard it for a moment in its more
philosophic aspect. We are at once struck with its self-dependence as
a machine, and even its resemblance in some respects to a living
creature. All its activity depends on the galvanic current. From
three separate sources invisible currents are led to its principal
parts, and are at once physically changed. That entering the mouse-mill
becomes transmuted in part into the mechanical motion of the revolving
drum, and part into electricity of a more intense nature--into mimic
lightning, in fact, with its accompaniments of heat and sound. That
entering the signal magnet expends part of its force in the magnetism
of the core. That entering the signal coil, which may be taken as the
brain of the instrument, appears to us as INTELLIGENCE.
The recorder is now in use in all four quarters of the globe, from
Northern Europe to Southern Brazil, from China to New England. Many and
complete are the adjustments for rendering it serviceable under a wide
range of electrical conditions and climatic changes.
Pages:
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135